ISO 10791-5:1998

Overview

ISO 10791-5:1998 is an international standard developed by ISO that focuses on the test conditions for machining centres, specifically addressing the accuracy and repeatability of positioning of work-holding pallets. Machining centres, which are numerically controlled (NC) machine tools, use pallets to efficiently hold and position workpieces for various machining operations such as milling, drilling, and tapping. Pallet systems are essential in automated manufacturing environments and flexible manufacturing systems (FMS), where consistent and precise positioning is crucial for quality and productivity.

This standard provides recommended tests for assessing the repeatability and total accuracy of pallet positioning on a given machining centre. It is a valuable resource for manufacturers, machine tool users, and quality assurance teams seeking to verify machine tool performance, compare equipment, or perform acceptance and maintenance checks.

Key Topics

• Test Methods: ISO 10791-5 specifies procedures for assessing:
  • Repeatability of positioning for individual pallets
  • Accuracy of positioning for a batch of pallets relative to the pallet receiver
• Measurement Instruments: The standard provides guidance on selecting and positioning measuring instruments, such as dial gauges, gauge blocks, and fixtures, ensuring results meet specified precision levels.
• Reference Standards: Contains requirements to refer to related standards, including ISO 230-1 (geometric accuracy) and ISO 230-2 (NC axis repeatability and accuracy).
• Tolerances: Defines acceptable tolerances for positioning deviations, considering pallet size and orientation, for both linear and rotary axes.
• Test Selection: Advises on selecting relevant tests based on machine configuration, agreement between users and manufacturers, and cost considerations.

Applications

ISO 10791-5:1998 is widely applicable in a range of industrial and manufacturing environments where precision machining centres are used. Typical applications include:

• Acceptance Testing: Machine tool manufacturers and buyers use this standard to ensure new equipment meets contractual performance requirements for pallet positioning.
• Quality Assurance and Inspection: Routine use in ongoing maintenance and quality control programs to detect deviations and ensure consistent product quality.
• Process Optimization: Identifying positioning errors allows manufacturers to optimize processes, reduce waste, and improve throughput in automated manufacturing systems.
• Comparative Analysis: Enables standardized comparison between different machining centres or setups within a facility.
• Maintenance Diagnostics: Establishes baseline measurements for monitoring wear and predicting service needs in pallet systems.

Related Standards

Implementation and effective use of ISO 10791-5:1998 often involve reference to several related international standards, such as:

• ISO 230-1: Test code for machine tools - Part 1: Geometric accuracy in no-load or finishing conditions
• ISO 230-2: Test code for machine tools - Part 2: Determination of accuracy and repeatability of positioning of numerically controlled axes
• ISO 8526-1: Modular units for machine tools - Workholding pallets up to 800 mm nominal size
• ISO 8526-2: Modular units for machine tools - Workholding pallets of nominal size greater than 800 mm
• ISO 841: Coordinate system and motion nomenclature for industrial automation systems

Practical Value

By adhering to ISO 10791-5:1998, organizations can achieve:

• Enhanced machining accuracy due to verified pallet positioning
• Reduced downtime and scrap from misaligned workpieces
• Consistency and traceability in both production and quality audit processes
• A common technical language for specifying and verifying machine tool performance, improving supplier-customer relationships

Implementing this standard helps ensure precision, productivity, and process reliability in modern CNC and automated machining environments.